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Author: Subject: How to deal with oil mist on vacuum pumps?
beerwiz
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[*] posted on 20-9-2018 at 15:14
How to deal with oil mist on vacuum pumps?


How do you deal with the oil mist coming out from the exhaust port on vacuum pumps?

When I have that thing running for a few hours the whole room fills up with oil mist and the air becomes unbreathable. What is the best way to deal with this to completely eliminate the oil mist from the indoor environment? I've seen some oil filters but it doesn't look like they completely eliminate the mist and the little bit that makes it through would still smoke up the whole room in a few hours.

I understand I can attach a hose to the exhaust and lead it outdoors but I don't want my neighbors to see chimney like smoke coming out of the window.
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JJay
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[*] posted on 20-9-2018 at 16:11


You can run the exhaust through cotton. It will catch most of the fine particles and can also make some pumps run much quieter.

I try to use a water aspirator instead whenever possible.




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Sidmadra
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[*] posted on 20-9-2018 at 16:13


First, change your oil to a heavier oil, like mineral oil or a heavier vacuum oil. I've had oils off-gas like that before when they were new oil that came with the vacuum pump, but I don't have issues with mineral oil that I get from the pharmacy.


If that doesn't work for some reason, invest in a cheap inline filter/fan, or fan to vent outside. You will need one eventually anyways when reactions go wrong or you have to deal with really stinky stuff, or just intense solvent vapors. What you're describing is actually the exact thing that made me vent my work space; that and other vapor buildup.

I wouldn't worry about your neighbors seeing "smoke" venting from your exhaust. When you have a fan continually blowing air out, the vapor does not have enough time to build up, and it is constantly mixing it with the outside air. With my workspace, I don't even have a carbon filter, I just vent the air directly outside. The only thing I've ever been able to "smell" more than 10 feet away from my workspace was when I was boiling off nitric acid. The fan exhaust is constantly mixing with the air outside, as well, the wind is usually moving air around so it's not building up directly outside of your workspace. A carbon filter wouldn't hurt you though.


You could also construct a makeshift fumehood with a carbon filter fan attached, and just put the vacuum pump under it so you don't have to vent outside, but I think using a heavier oil will go a long ways for the problem you're having.


[Edited on 21-9-2018 by Sidmadra]
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beerwiz
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[*] posted on 20-9-2018 at 16:19


Quote: Originally posted by Sidmadra  
First, change your oil to a heavier oil, like mineral oil or a heavier vacuum oil. I've had oils off-gas like that before when they were new oil that came with the vacuum pump, but I don't have issues with mineral oil that I get from the pharmacy.
[Edited on 21-9-2018 by Sidmadra]


Are you saying I can use plain old mineral oil from the pharmacy as a high vacuum pump oil? If so, then I'll give that a try.

[Edited on 21-9-2018 by beerwiz]
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Sidmadra
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[*] posted on 20-9-2018 at 16:25


Quote: Originally posted by beerwiz  

Are you saying I can use plain old mineral oil from the pharmacy as a high vacuum pump oil? If so, then I'll give that a try.


Yeah that's pretty much all I use - with it I've actually noted the pump goes to a lower vacuum than what it's rated for. Instead of 0.075mmhg, I get down to like 0.05 sometimes.

There are probably better dedicated vacuum oils, but mineral oil works for me. I do occasionally have slight vapor coming from the vacuum, but I've heard people say this is just moisture off gasing. In any case, mineral oil doesn't smoke out the room like some oils I've had before.

[Edited on 21-9-2018 by Sidmadra]
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Dr.Bob
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[*] posted on 20-9-2018 at 17:48


They make mist catching filters that go on the exhaust. They slow down the roughing, but don't really hurt the final achieved vacuum much, so we use them where we cant vent them.
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Magpie
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[*] posted on 20-9-2018 at 18:20


Seal your system so no gases (includes air) are moving through the pump. Or at least minimize the gas flow.



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S.C. Wack
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[*] posted on 20-9-2018 at 18:32


I have one of those mist filters now but have been known to cover loosely with a rag. Does no one do chemistry in kitchens or bathrooms anymore.



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macckone
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[*] posted on 20-9-2018 at 18:35


an old sock makes a good filter.
You can also put a regular shop vac near the outlet.
Mine came from costco and has a hepa filter. It cost me $30.
I wouldn't trust it with toxic gasses or acids but I am certain it would remove 99% of particulates including oil mist.
You also can't seal a shop vac to the vacuum pump outlet since most shop vacs need air flow to cool the motor.
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Sulaiman
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[*] posted on 20-9-2018 at 23:38


My hvac pump came with a small wire wool oil mist filter
a little mist can occasionally be seen escaping,
but an invisible mist coats anything nearby with a film of dust-catching oil..

The worst noise comes from the exhaust port
so using a length of pipe to vent from exhaust port to outdoors or far away
saves you from the mist, and the noise, and any gasses that escape.

Eventually oil will drip from the end of the hose - possibly creating a fire and/or slip hazard.

I would prefer not to use a vacuum cleaner due to the noise.

[Edited on 21-9-2018 by Sulaiman]
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Magpie
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[*] posted on 21-9-2018 at 09:12


If there are no gases going through your pump you will have no oil mist. I don't get any mist except at startup when the system is being evacuated of air.



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weilawei
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[*] posted on 22-9-2018 at 01:02


If you've got a gas ballast on your pump, you'll see a mist as long as that's open, also. Mine has an oil mist filter with a tube on the exhaust to lead it to a fan to be mixed with air and exhausted.
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